Passenger vehicles often include electric batteries for operating features of a vehicle's electrical and drivetrain systems. For example, in a hybrid-electric vehicle (“HEV”), a plug-in hybrid electric vehicle (“PHEV”), a fuel cell electric vehicle (“FCEV”), or a purely electric vehicle (“EV”), an energy storage system (“ESS”) (e.g., a rechargeable ESS) may be used to power electric drivetrain components of the vehicle (e.g., electric drive motors and the like). The ESS may store high-voltage electrical energy, which may be transmitted to vehicle systems via a high-voltage (“HV”) bus having positive and negative conductors or rails. The ESS may be selectively coupled to the positive and negative conductors or rails via one or more selectively switched electric contactors.
Contacts in a HV contactor may be held open by a spring and/or another mechanical means. To close the contactor, an actuator coil in the contactor may be energized to move the contacts against the bias of the spring and/or mechanical means, thereby closing the contactor. In some circumstances, contacts in the HV contactor may experience electrical arcing when actuated. Such arcing may cause the contacts to become welded and/or partially welded together (e.g., when contacts may remain closed and/or partially closed after the actuator coil is de-energized), potentially resulting in certain undesirable conditions. Conventional systems and methods for detected welded contactors (e.g., using current rise time only) may identify welded contactors in some instances, but may nevertheless still allow certain welded and/or partially welded contactors to go undetected and may be restricted for use in connection a limited set of contactor designs.